The functions of and changes in proteins occuring in regenerating nerves will be examined. Proteins in regenerating axons and sprouts will be labeled in cell bodies and, after slow and fast axonal transport, will be analyzed upon arrival at terminals. The lifetimes, modifications and processing of such proteins will be examined in both synaptic terminals and regenerating axons by two dimensional gel electrophoresis. Neurons from fish and frogs will be studied. The modifications in membrane proteins and states of polymerization of cytoskeletal proteins during regeneration will be described. Changes in protein synthesis in glial cells during nerve degeneration and regeneration also will be analyzed. We will be testing hypothesis for analyzing the failure of most central nervous system neurons to regenerate. We hope to identify the sequence of biochemical events underlying the reorganization of damaged nerves for regeneration.